Report from Special Advisor (contribution to) NI Assemble, Committee for the Environment, Report on the Committee’s Inquiry into Wind Energy

Research output: Book/ReportCommissioned report

Abstract

Overview – keypointsAcoustic terms: LAeq,T is the ‘average’ of the total sound. LA90,T is the background sound when the loudest elements are ignored. LAeqT and L90 do not take account of the type of the sound. Sound reduces with increasing distance from the source and is affected by weather and the landscape. At a distance of 1km you mainly only hear the low pitch (frequency) sounds.Mechanical noise from wind turbines is generally the result of faults or wear and tear. Most wind turbine noise is not mechanical, it is aerodynamic noise ie ‘swish’. The sound from turbine blades is not steady, it fluctuates, this is called amplitude modulation (AM). Wind turbine noise can also contain noticeable tones. Generally, sounds containing tones more annoying. Wind turbine noise is more annoying than transport noise or noise from other industries. Reasons for recommendation that ETSU-R-97 is updatedModern wind turbines are considerably larger now than in those that were in place in 1997, this can result in more lower frequency noise and an increased risk of AM due to high level wind fluctuations. ETSU - R - 97 The Assessment and Rating of Noise from Wind Farms’ is influenced by BS4142 Method for rating industrial noise affecting mixed residential and industrial areas. BS4142 is currently being updated. The draft revised BS4142 includes further emphasis on the annoyance from tones and fluctuations. The draft proposes that when both characteristics are present the two should individually be taken into account.The WHO guidance for indoor noise levels at night was 35dB when ETSU-R-97 was published in 1997, it has now been revised to 30dBETSU-R-97 advises using the LA90,10min noise index for both turbine and background noise. Most other relevant standards use LAeq for source noise. LA90 was adopted by ETSU-R-97 as it was assumed at the time of drafting that wind turbine noise was relatively steady and characterless. Evidence and knowledge since 1997 has highlighted that certain wind farms/single wind turbines produce AM and hence the original assumption within ETSU-R-97 that wind turbine noise was relatively steady and characterless no longer holds true. ETSU-R-97 needs to be updated to take account of much greater understanding of the acoustics of large wind turbines and the annoyance/health effects of wind turbine noise. In particular, consideration of the following content of ETSU-R-97 is recommended: • The statement that it is not necessary to use a margin above background approach in low-noise environments• The use of LA90 for both the background noise and the wind farm noise • Night time limit of 43dBA bearing in mind the revised WHO guidelines• The assumption that background noise rises with increasing wind speed• The consideration of fluctuations and tones.Specific issuesMore recent designs of wind turbines are much quieter than older designs. Many industries are required to apply Best Available Techniques (BAT) to prevent noise disturbances. The enquiry may wish to consider the age and type of turbines being proposed for installation in Northern Ireland. Anecdotally, many “new” wind turbines installed in Northern Ireland (NI) are in fact reconditioned turbines. On-going, long term monitoring by the developer would enable the continuing noise exposure of the nearby residents to be determined and increases in noise, beyond the predicted and permitted levels, to be identified and remedied.It is common practice for local planning authorities to set planning conditions to control or reduce noise levels, or to mitigate the impact of noise. Examples relating to wind turbine noise are provided in the IOA Good practice guide to the application of ETSU-R-97.There is a great deal of expertise within the Environmental Health profession in Northern Ireland’s district councils. There is a considerable burden, on individual councils, associated with contributing to planning applications regarding wind turbines.It is suggested that a more strategic approach to both single turbine and wind farm applications would be beneficial, as opposed to the ad hoc approach currently employed in Northern Ireland. Danish policy The Danish policy includes• a replacement Scheme for Wind turbines on land • a recent emphasis on a planned and coordinated development of offshore wind farms • a loss of value scheme for dwellings• the option to purchase scheme. Erectors of large wind turbines shall offer for sale at least 20% of the wind turbine project to the local population.
LanguageEnglish
Number of pages2
Publication statusPublished - 29 Jan 2015

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wind turbine
energy
wind farm
turbine
strategic approach
local planning
industry

Keywords

  • Wind turbine
  • noise
  • environment
  • acoustics

Cite this

@book{c1dc185541414cbdad0dc11d364feedb,
title = "Report from Special Advisor (contribution to) NI Assemble, Committee for the Environment, Report on the Committee’s Inquiry into Wind Energy",
abstract = "Overview – keypointsAcoustic terms: LAeq,T is the ‘average’ of the total sound. LA90,T is the background sound when the loudest elements are ignored. LAeqT and L90 do not take account of the type of the sound. Sound reduces with increasing distance from the source and is affected by weather and the landscape. At a distance of 1km you mainly only hear the low pitch (frequency) sounds.Mechanical noise from wind turbines is generally the result of faults or wear and tear. Most wind turbine noise is not mechanical, it is aerodynamic noise ie ‘swish’. The sound from turbine blades is not steady, it fluctuates, this is called amplitude modulation (AM). Wind turbine noise can also contain noticeable tones. Generally, sounds containing tones more annoying. Wind turbine noise is more annoying than transport noise or noise from other industries. Reasons for recommendation that ETSU-R-97 is updatedModern wind turbines are considerably larger now than in those that were in place in 1997, this can result in more lower frequency noise and an increased risk of AM due to high level wind fluctuations. ETSU - R - 97 The Assessment and Rating of Noise from Wind Farms’ is influenced by BS4142 Method for rating industrial noise affecting mixed residential and industrial areas. BS4142 is currently being updated. The draft revised BS4142 includes further emphasis on the annoyance from tones and fluctuations. The draft proposes that when both characteristics are present the two should individually be taken into account.The WHO guidance for indoor noise levels at night was 35dB when ETSU-R-97 was published in 1997, it has now been revised to 30dBETSU-R-97 advises using the LA90,10min noise index for both turbine and background noise. Most other relevant standards use LAeq for source noise. LA90 was adopted by ETSU-R-97 as it was assumed at the time of drafting that wind turbine noise was relatively steady and characterless. Evidence and knowledge since 1997 has highlighted that certain wind farms/single wind turbines produce AM and hence the original assumption within ETSU-R-97 that wind turbine noise was relatively steady and characterless no longer holds true. ETSU-R-97 needs to be updated to take account of much greater understanding of the acoustics of large wind turbines and the annoyance/health effects of wind turbine noise. In particular, consideration of the following content of ETSU-R-97 is recommended: • The statement that it is not necessary to use a margin above background approach in low-noise environments• The use of LA90 for both the background noise and the wind farm noise • Night time limit of 43dBA bearing in mind the revised WHO guidelines• The assumption that background noise rises with increasing wind speed• The consideration of fluctuations and tones.Specific issuesMore recent designs of wind turbines are much quieter than older designs. Many industries are required to apply Best Available Techniques (BAT) to prevent noise disturbances. The enquiry may wish to consider the age and type of turbines being proposed for installation in Northern Ireland. Anecdotally, many “new” wind turbines installed in Northern Ireland (NI) are in fact reconditioned turbines. On-going, long term monitoring by the developer would enable the continuing noise exposure of the nearby residents to be determined and increases in noise, beyond the predicted and permitted levels, to be identified and remedied.It is common practice for local planning authorities to set planning conditions to control or reduce noise levels, or to mitigate the impact of noise. Examples relating to wind turbine noise are provided in the IOA Good practice guide to the application of ETSU-R-97.There is a great deal of expertise within the Environmental Health profession in Northern Ireland’s district councils. There is a considerable burden, on individual councils, associated with contributing to planning applications regarding wind turbines.It is suggested that a more strategic approach to both single turbine and wind farm applications would be beneficial, as opposed to the ad hoc approach currently employed in Northern Ireland. Danish policy The Danish policy includes• a replacement Scheme for Wind turbines on land • a recent emphasis on a planned and coordinated development of offshore wind farms • a loss of value scheme for dwellings• the option to purchase scheme. Erectors of large wind turbines shall offer for sale at least 20{\%} of the wind turbine project to the local population.",
keywords = "Wind turbine, noise, environment, acoustics",
author = "Ursula Walsh",
note = "Reference text: British Standards Institution BS 4142:1997 Method for rating industrial noise affecting mixed residential and industrial areas, BSI ISBN 0 580 28300 3. British Standards Institution BS 7445:1991 Description and measurement of environmental noise: Part 1. Guide to quantities and procedures, BSI, ISBN 0 580 19728 X Canadian Wind Energy Association (2007). Position on Setbacks for Large-Scale Wind Turbines in Rural Areas (MOE Class 3) in Ontario CONCAWE 1981 The propagation of noise from petroleum and petrochemical complexes to neighbouring communities, Danish Energy Agency. 2009 Wind Turbines in Denmark. Danish Energy Agency. DEFRA 2011 AECOM Wind Farm Noise Complaint Methodology NANR 277 23. DEFRA Di Napoli, C. 2009 Case study: Wind turbine noise in a small and quiet community in Finland, proc.3rd Int. Meeting on Wind Turbine Noise, {\AA}lborg Environment Agency 2004 IPPC Horizontal Guidance for Noise (IPPC H3) Part 2 Noise Assessment and Control Environmental Noise Directive Directive 2002/49/EC, 2002 European Parliament and of the Council ETSU-R-97, (1997) The assessment and rating of noise from wind farms: Guski, R. 1997 Conceptual. Methodological, an Dose – response problems related to annoyance and disturbance, Inter-Noise 97, pg 1077-1082 - at pg 1077 highlights issues of the different meaning of the term annoyance across different languages and cultures Haugen, K. M. B. (2011). International Review of Policies and Recommendations for Wind Turbine Setbacks from Residences: Noise, Shadow Flicker and Other Concerns. Minnesota Department of Commerce: Energy Facility Permitting. Hayes, M.D. (1996): The measurement of noise from wind farms and background noise levels - Proceedings of Internoise 96, 471-478, Liverpool. Hayes Mckenzie report, 2006 The measurement of low frequency noise at three UK wind farms, Hayes Mckenzie Partnership Ltd, report to the Department of Trade and Industry Hayes McKenzie Partnership Ltd. 2011 Report on “Analysis of How Noise Impacts are considered in the Determination of Wind Farm Planning Applications” Ref HM: 2293/R1 HPA 2010. Environmental Noise and Health in the UK - A report by the Ad Hoc Expert Group on Noise and Health. HPA ISO 9613 Acoustics - Attenuation of sound during propagation outdoors; Part 1: 1993 Calculation of the absorption of sound by the atmosphere; Part 2: 1996 General method of calculation. Irish Environmental Protection Agency Integrated Pollution Control Licensing, Guidance Note for Noise In Relation to Scheduled Activities, Irish Environmental Protection Agency, 1995. Leventhall, H. G. 2004 Low frequency noise and annoyance. Noise Health;6:59-72 Leventhall, H. G., Pelmear, P., Benton, S. 2003. A Review of Published Research on Low Frequency Noise and its Effects Report for Defra Leventhall, H.G., Benton, S. and Robertson, D. (2008). Coping strategies for low frequency noise. J Low Frequency Noise Vib, 27(1), 35–52. Madison Wind Advisory Committee, 2013. Report of Town of Madison Wind Advisory Committee, APPENDIX A – DRAFT #2 APPENDIX A – DRAFT #2 January 9, 2013, Madison Wind Advisory Committee Maris, E., Stallen, P.J. M., Steensma, H., Vermunt, R. (2006) (Un)Sound management -Three laboratory experiments on the effects of social non-acoustical determinants of noise annoyance. INTER-NOISE 2006 3-6 DECEMBER 2006 HONOLULU, HAWAII, USA Maris, E. Stallen, P.J. M., Steensma, H., Vermunt, R. 2007 - Evaluating noise in social context: the effect of procedural unfairness on noise annoyance judgments. J Acoust Soc Am. 2007 Dec;122(6):3483-94. Maschke, C. 2004 Introduction to the special issue on low frequency noise. Health 6: 1-2 Moller, H. & Pedersen, C. S. (2011) Low-frequency noise from large wind turbines. J. Acoust. Soc. Am. 129, 3727 Moorhouse, A.T., Hayes, M., von H{\"u}nerbein, S., Piper, B.J. and Adams, M.D. 2007, Research into aerodynamic modulation of wind turbine noise: final report , Technical Report, Department for Business, Enterprise and Regulatory Reform, UK Noise Emission in the Environment by Equipment for use Outdoors Regulations 2001, SI No. 1701, HMSO ISBN 0 11029485 8. North Yorkshire County Council, 2012 Renewable Energy Policy: Proximity of homes to wind turbines. North Yorkshire County Council Oerlemans, S., Lopez, B.M. 2005 Localisation and quantification of noise sources on a wind turbine, Wind Turbine Noise: Perspectives for Control Berlin 17th and 18th October 2005 Pedersen, E. 2007 Human Response to Wind Farm Noise – Perception Annoyance and Moderating Factors, Occupational and Environmental Medicine, Dept of Public Health and Community Medicine, Institute of Medicine, The Sahlgrenska Academy, G{\"o}teborg, Sweden . Pedersen, E., Persson Waye, K. (2007) Wind turbine noise, annoyance and self-reported health and well-being in different living environments. Occup. Environ. Med. 64, 480–486. Pedersen, E. 2003 “Noise Annoyance from Wind Turbines – a Review.” Swedish Environmental Protection Agency, Report 5308, August 2003. Pedersen, E. and Persson-Waye, K. 2004. Perception and annoyance due to wind turbine noise–a dose-response relationship , Journal of the Acoustical Society of America, 116 (6), 2004, 3460-3470 Persson, K., Bj{\"o}rkman, M., and Rylander, R. (1990): Loudness, annoyance and the dBA in evaluating low frequency sounds. Jnl Low Freq Noise Vibn 9, 32-45.; Persson, K., and Bjorkman, M. (1988): Annoyance due to low frequency noise and the use of the dB(A) scale. J Sound Vibration 127, 491-497.; Persson-Waye, K. (2004) Effects of low frequency noise on sleep. Noise Health 2004;6:87-91 Peters, R. J., Smith, B. J. and Hollins, M. 2011 ' Acoustics and Noise Control ' Third Edition Prentice-Hall Planning Policy Guidance Note PPG24: Planning and Noise, 1994, DoE. Planning Policy Statement (PPS) 22, 2004. Office of the Deputy Prime Minister. Planning Policy Statement 18, Renewable Energy 2009. Planning and Environmental Policy Group, Department of the Environmental for Northern Ireland Best Practice Guidance to Planning Policy Statement 18, Renewable Energy 2009. Planning and Environmental Policy Group, Department of the Environmental for Northern Ireland Planning Policy Statement 18, Best Practice Guide to Renewable Energy 2009. Planning and Environmental Policy Group, Department of the Environmental for Northern Ireland Poulsen, T. (2002): Laboratory determination of annoyance of low frequency noise. 10th International Meeting Low Frequency Noise and VIbration and its Control. York UK (Editor: H G Leventhall), 19-26, pp. 19¬28. Poulsen, T., and Mortensen, F. R. (2002): Laboratory evaluation of annoyance of low frequency noise. Working Report No.1 2002 Danish Environmental Protection Agency. University of Salford. NANR233 Research into aerodynamic modulation of wind turbine noise. DEFRA Van Den Berg, G.P. 2005 The Beat is Getting Stronger: The Effect of Atmospheric Stability on Low Frequency Modulated Sound of Wind Turbines, Journal of Low Frequency Noise & Vibration and Active Control, Volume 24, Number 1 / March 2005 Van Den Berg, G. P., 2009 Why is wind turbine noise noisier than other noise?, Proceedings of Euronoise, Edinburgh, October 2009 Van Den Berg, G. P., 2006 The sounds of high winds‖ (doctoral thesis), University of Groningen Welsh Assembly Government (WAG) 2005 Technical Advice Note 8: Planning for Renewable Energy, July, Cardiff: WAG WHO (1980). Noise. Environmental Health Criteria Document No. 12. Geneva, Switzerland: World Health Organization. WHO (1999). Guidelines for Community Noise (B Berglund et al, eds). Geneva, Switzerland: World Health Organization.",
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N1 - Reference text: British Standards Institution BS 4142:1997 Method for rating industrial noise affecting mixed residential and industrial areas, BSI ISBN 0 580 28300 3. British Standards Institution BS 7445:1991 Description and measurement of environmental noise: Part 1. Guide to quantities and procedures, BSI, ISBN 0 580 19728 X Canadian Wind Energy Association (2007). Position on Setbacks for Large-Scale Wind Turbines in Rural Areas (MOE Class 3) in Ontario CONCAWE 1981 The propagation of noise from petroleum and petrochemical complexes to neighbouring communities, Danish Energy Agency. 2009 Wind Turbines in Denmark. Danish Energy Agency. DEFRA 2011 AECOM Wind Farm Noise Complaint Methodology NANR 277 23. DEFRA Di Napoli, C. 2009 Case study: Wind turbine noise in a small and quiet community in Finland, proc.3rd Int. Meeting on Wind Turbine Noise, Ålborg Environment Agency 2004 IPPC Horizontal Guidance for Noise (IPPC H3) Part 2 Noise Assessment and Control Environmental Noise Directive Directive 2002/49/EC, 2002 European Parliament and of the Council ETSU-R-97, (1997) The assessment and rating of noise from wind farms: Guski, R. 1997 Conceptual. Methodological, an Dose – response problems related to annoyance and disturbance, Inter-Noise 97, pg 1077-1082 - at pg 1077 highlights issues of the different meaning of the term annoyance across different languages and cultures Haugen, K. M. B. (2011). International Review of Policies and Recommendations for Wind Turbine Setbacks from Residences: Noise, Shadow Flicker and Other Concerns. Minnesota Department of Commerce: Energy Facility Permitting. Hayes, M.D. (1996): The measurement of noise from wind farms and background noise levels - Proceedings of Internoise 96, 471-478, Liverpool. Hayes Mckenzie report, 2006 The measurement of low frequency noise at three UK wind farms, Hayes Mckenzie Partnership Ltd, report to the Department of Trade and Industry Hayes McKenzie Partnership Ltd. 2011 Report on “Analysis of How Noise Impacts are considered in the Determination of Wind Farm Planning Applications” Ref HM: 2293/R1 HPA 2010. Environmental Noise and Health in the UK - A report by the Ad Hoc Expert Group on Noise and Health. HPA ISO 9613 Acoustics - Attenuation of sound during propagation outdoors; Part 1: 1993 Calculation of the absorption of sound by the atmosphere; Part 2: 1996 General method of calculation. Irish Environmental Protection Agency Integrated Pollution Control Licensing, Guidance Note for Noise In Relation to Scheduled Activities, Irish Environmental Protection Agency, 1995. Leventhall, H. G. 2004 Low frequency noise and annoyance. Noise Health;6:59-72 Leventhall, H. G., Pelmear, P., Benton, S. 2003. A Review of Published Research on Low Frequency Noise and its Effects Report for Defra Leventhall, H.G., Benton, S. and Robertson, D. (2008). Coping strategies for low frequency noise. J Low Frequency Noise Vib, 27(1), 35–52. Madison Wind Advisory Committee, 2013. Report of Town of Madison Wind Advisory Committee, APPENDIX A – DRAFT #2 APPENDIX A – DRAFT #2 January 9, 2013, Madison Wind Advisory Committee Maris, E., Stallen, P.J. M., Steensma, H., Vermunt, R. (2006) (Un)Sound management -Three laboratory experiments on the effects of social non-acoustical determinants of noise annoyance. INTER-NOISE 2006 3-6 DECEMBER 2006 HONOLULU, HAWAII, USA Maris, E. Stallen, P.J. M., Steensma, H., Vermunt, R. 2007 - Evaluating noise in social context: the effect of procedural unfairness on noise annoyance judgments. J Acoust Soc Am. 2007 Dec;122(6):3483-94. Maschke, C. 2004 Introduction to the special issue on low frequency noise. Health 6: 1-2 Moller, H. & Pedersen, C. S. (2011) Low-frequency noise from large wind turbines. J. Acoust. Soc. Am. 129, 3727 Moorhouse, A.T., Hayes, M., von Hünerbein, S., Piper, B.J. and Adams, M.D. 2007, Research into aerodynamic modulation of wind turbine noise: final report , Technical Report, Department for Business, Enterprise and Regulatory Reform, UK Noise Emission in the Environment by Equipment for use Outdoors Regulations 2001, SI No. 1701, HMSO ISBN 0 11029485 8. North Yorkshire County Council, 2012 Renewable Energy Policy: Proximity of homes to wind turbines. North Yorkshire County Council Oerlemans, S., Lopez, B.M. 2005 Localisation and quantification of noise sources on a wind turbine, Wind Turbine Noise: Perspectives for Control Berlin 17th and 18th October 2005 Pedersen, E. 2007 Human Response to Wind Farm Noise – Perception Annoyance and Moderating Factors, Occupational and Environmental Medicine, Dept of Public Health and Community Medicine, Institute of Medicine, The Sahlgrenska Academy, Göteborg, Sweden . Pedersen, E., Persson Waye, K. (2007) Wind turbine noise, annoyance and self-reported health and well-being in different living environments. Occup. Environ. Med. 64, 480–486. Pedersen, E. 2003 “Noise Annoyance from Wind Turbines – a Review.” Swedish Environmental Protection Agency, Report 5308, August 2003. Pedersen, E. and Persson-Waye, K. 2004. Perception and annoyance due to wind turbine noise–a dose-response relationship , Journal of the Acoustical Society of America, 116 (6), 2004, 3460-3470 Persson, K., Björkman, M., and Rylander, R. (1990): Loudness, annoyance and the dBA in evaluating low frequency sounds. Jnl Low Freq Noise Vibn 9, 32-45.; Persson, K., and Bjorkman, M. (1988): Annoyance due to low frequency noise and the use of the dB(A) scale. J Sound Vibration 127, 491-497.; Persson-Waye, K. (2004) Effects of low frequency noise on sleep. Noise Health 2004;6:87-91 Peters, R. J., Smith, B. J. and Hollins, M. 2011 ' Acoustics and Noise Control ' Third Edition Prentice-Hall Planning Policy Guidance Note PPG24: Planning and Noise, 1994, DoE. Planning Policy Statement (PPS) 22, 2004. Office of the Deputy Prime Minister. Planning Policy Statement 18, Renewable Energy 2009. Planning and Environmental Policy Group, Department of the Environmental for Northern Ireland Best Practice Guidance to Planning Policy Statement 18, Renewable Energy 2009. Planning and Environmental Policy Group, Department of the Environmental for Northern Ireland Planning Policy Statement 18, Best Practice Guide to Renewable Energy 2009. Planning and Environmental Policy Group, Department of the Environmental for Northern Ireland Poulsen, T. (2002): Laboratory determination of annoyance of low frequency noise. 10th International Meeting Low Frequency Noise and VIbration and its Control. York UK (Editor: H G Leventhall), 19-26, pp. 19¬28. Poulsen, T., and Mortensen, F. R. (2002): Laboratory evaluation of annoyance of low frequency noise. Working Report No.1 2002 Danish Environmental Protection Agency. University of Salford. NANR233 Research into aerodynamic modulation of wind turbine noise. DEFRA Van Den Berg, G.P. 2005 The Beat is Getting Stronger: The Effect of Atmospheric Stability on Low Frequency Modulated Sound of Wind Turbines, Journal of Low Frequency Noise & Vibration and Active Control, Volume 24, Number 1 / March 2005 Van Den Berg, G. P., 2009 Why is wind turbine noise noisier than other noise?, Proceedings of Euronoise, Edinburgh, October 2009 Van Den Berg, G. P., 2006 The sounds of high winds‖ (doctoral thesis), University of Groningen Welsh Assembly Government (WAG) 2005 Technical Advice Note 8: Planning for Renewable Energy, July, Cardiff: WAG WHO (1980). Noise. Environmental Health Criteria Document No. 12. Geneva, Switzerland: World Health Organization. WHO (1999). Guidelines for Community Noise (B Berglund et al, eds). Geneva, Switzerland: World Health Organization.

PY - 2015/1/29

Y1 - 2015/1/29

N2 - Overview – keypointsAcoustic terms: LAeq,T is the ‘average’ of the total sound. LA90,T is the background sound when the loudest elements are ignored. LAeqT and L90 do not take account of the type of the sound. Sound reduces with increasing distance from the source and is affected by weather and the landscape. At a distance of 1km you mainly only hear the low pitch (frequency) sounds.Mechanical noise from wind turbines is generally the result of faults or wear and tear. Most wind turbine noise is not mechanical, it is aerodynamic noise ie ‘swish’. The sound from turbine blades is not steady, it fluctuates, this is called amplitude modulation (AM). Wind turbine noise can also contain noticeable tones. Generally, sounds containing tones more annoying. Wind turbine noise is more annoying than transport noise or noise from other industries. Reasons for recommendation that ETSU-R-97 is updatedModern wind turbines are considerably larger now than in those that were in place in 1997, this can result in more lower frequency noise and an increased risk of AM due to high level wind fluctuations. ETSU - R - 97 The Assessment and Rating of Noise from Wind Farms’ is influenced by BS4142 Method for rating industrial noise affecting mixed residential and industrial areas. BS4142 is currently being updated. The draft revised BS4142 includes further emphasis on the annoyance from tones and fluctuations. The draft proposes that when both characteristics are present the two should individually be taken into account.The WHO guidance for indoor noise levels at night was 35dB when ETSU-R-97 was published in 1997, it has now been revised to 30dBETSU-R-97 advises using the LA90,10min noise index for both turbine and background noise. Most other relevant standards use LAeq for source noise. LA90 was adopted by ETSU-R-97 as it was assumed at the time of drafting that wind turbine noise was relatively steady and characterless. Evidence and knowledge since 1997 has highlighted that certain wind farms/single wind turbines produce AM and hence the original assumption within ETSU-R-97 that wind turbine noise was relatively steady and characterless no longer holds true. ETSU-R-97 needs to be updated to take account of much greater understanding of the acoustics of large wind turbines and the annoyance/health effects of wind turbine noise. In particular, consideration of the following content of ETSU-R-97 is recommended: • The statement that it is not necessary to use a margin above background approach in low-noise environments• The use of LA90 for both the background noise and the wind farm noise • Night time limit of 43dBA bearing in mind the revised WHO guidelines• The assumption that background noise rises with increasing wind speed• The consideration of fluctuations and tones.Specific issuesMore recent designs of wind turbines are much quieter than older designs. Many industries are required to apply Best Available Techniques (BAT) to prevent noise disturbances. The enquiry may wish to consider the age and type of turbines being proposed for installation in Northern Ireland. Anecdotally, many “new” wind turbines installed in Northern Ireland (NI) are in fact reconditioned turbines. On-going, long term monitoring by the developer would enable the continuing noise exposure of the nearby residents to be determined and increases in noise, beyond the predicted and permitted levels, to be identified and remedied.It is common practice for local planning authorities to set planning conditions to control or reduce noise levels, or to mitigate the impact of noise. Examples relating to wind turbine noise are provided in the IOA Good practice guide to the application of ETSU-R-97.There is a great deal of expertise within the Environmental Health profession in Northern Ireland’s district councils. There is a considerable burden, on individual councils, associated with contributing to planning applications regarding wind turbines.It is suggested that a more strategic approach to both single turbine and wind farm applications would be beneficial, as opposed to the ad hoc approach currently employed in Northern Ireland. Danish policy The Danish policy includes• a replacement Scheme for Wind turbines on land • a recent emphasis on a planned and coordinated development of offshore wind farms • a loss of value scheme for dwellings• the option to purchase scheme. Erectors of large wind turbines shall offer for sale at least 20% of the wind turbine project to the local population.

AB - Overview – keypointsAcoustic terms: LAeq,T is the ‘average’ of the total sound. LA90,T is the background sound when the loudest elements are ignored. LAeqT and L90 do not take account of the type of the sound. Sound reduces with increasing distance from the source and is affected by weather and the landscape. At a distance of 1km you mainly only hear the low pitch (frequency) sounds.Mechanical noise from wind turbines is generally the result of faults or wear and tear. Most wind turbine noise is not mechanical, it is aerodynamic noise ie ‘swish’. The sound from turbine blades is not steady, it fluctuates, this is called amplitude modulation (AM). Wind turbine noise can also contain noticeable tones. Generally, sounds containing tones more annoying. Wind turbine noise is more annoying than transport noise or noise from other industries. Reasons for recommendation that ETSU-R-97 is updatedModern wind turbines are considerably larger now than in those that were in place in 1997, this can result in more lower frequency noise and an increased risk of AM due to high level wind fluctuations. ETSU - R - 97 The Assessment and Rating of Noise from Wind Farms’ is influenced by BS4142 Method for rating industrial noise affecting mixed residential and industrial areas. BS4142 is currently being updated. The draft revised BS4142 includes further emphasis on the annoyance from tones and fluctuations. The draft proposes that when both characteristics are present the two should individually be taken into account.The WHO guidance for indoor noise levels at night was 35dB when ETSU-R-97 was published in 1997, it has now been revised to 30dBETSU-R-97 advises using the LA90,10min noise index for both turbine and background noise. Most other relevant standards use LAeq for source noise. LA90 was adopted by ETSU-R-97 as it was assumed at the time of drafting that wind turbine noise was relatively steady and characterless. Evidence and knowledge since 1997 has highlighted that certain wind farms/single wind turbines produce AM and hence the original assumption within ETSU-R-97 that wind turbine noise was relatively steady and characterless no longer holds true. ETSU-R-97 needs to be updated to take account of much greater understanding of the acoustics of large wind turbines and the annoyance/health effects of wind turbine noise. In particular, consideration of the following content of ETSU-R-97 is recommended: • The statement that it is not necessary to use a margin above background approach in low-noise environments• The use of LA90 for both the background noise and the wind farm noise • Night time limit of 43dBA bearing in mind the revised WHO guidelines• The assumption that background noise rises with increasing wind speed• The consideration of fluctuations and tones.Specific issuesMore recent designs of wind turbines are much quieter than older designs. Many industries are required to apply Best Available Techniques (BAT) to prevent noise disturbances. The enquiry may wish to consider the age and type of turbines being proposed for installation in Northern Ireland. Anecdotally, many “new” wind turbines installed in Northern Ireland (NI) are in fact reconditioned turbines. On-going, long term monitoring by the developer would enable the continuing noise exposure of the nearby residents to be determined and increases in noise, beyond the predicted and permitted levels, to be identified and remedied.It is common practice for local planning authorities to set planning conditions to control or reduce noise levels, or to mitigate the impact of noise. Examples relating to wind turbine noise are provided in the IOA Good practice guide to the application of ETSU-R-97.There is a great deal of expertise within the Environmental Health profession in Northern Ireland’s district councils. There is a considerable burden, on individual councils, associated with contributing to planning applications regarding wind turbines.It is suggested that a more strategic approach to both single turbine and wind farm applications would be beneficial, as opposed to the ad hoc approach currently employed in Northern Ireland. Danish policy The Danish policy includes• a replacement Scheme for Wind turbines on land • a recent emphasis on a planned and coordinated development of offshore wind farms • a loss of value scheme for dwellings• the option to purchase scheme. Erectors of large wind turbines shall offer for sale at least 20% of the wind turbine project to the local population.

KW - Wind turbine

KW - noise

KW - environment

KW - acoustics

M3 - Commissioned report

BT - Report from Special Advisor (contribution to) NI Assemble, Committee for the Environment, Report on the Committee’s Inquiry into Wind Energy

ER -